Gaia talk by Dr George Seabroke - Data Access

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JohnM
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Gaia talk by Dr George Seabroke - Data Access

Post by JohnM »

In the talk about Gaia today Dr George Seabroke showed the URL that allows you to access the Gaia EDR3 data

The URL is https://gea.esac.esa.int/archive/

For simple queries either of a particular star or by location they provide a tab for the 'Basic' interface.

You can either enter the name of the star you are interested in in the box having selected the name button or else select the equatorial button and enter the position. When you type the star name into the box it will show that it has been resolved into a position if the object exists in any of the 3 databases it checks.

If required you can enter the search radius and select either a circle or box about the position. When you select the search radius don't make it too large as otherwise you may be overwhelmed by the number of results returned ! Note the drop down box normally has a limit of 500 but you can increase it to 2000 if required.

At that point you can click 'Submit Query' and the results should appear in the 'Query Results Tab' . The query as set returns only a limited number of the columns of data about the stars. If you want more click on the 'Basic' Tab ( don't use the back button in the browser it exits the query page !) then select the display columns drop down. This allows you to select the columns to be displayed. Some are quite esoteric but there are quite a lot of useful ones depending on what you are trying to achieve. In particular the Proper motion (in RA & Dec) might be useful but more likley the magnitude in the three bands phot_g_man magnitude will probably already be selected but the bp & rp magnitudes (Gaia Blue & Red filters) give colour information.

The bp_rp colour column should already be selected but the bp-g & g-rp are also avaialble.

To help you a 'tool tip' pops up when you hover over the labels. This also shows the units (where applicable) Having selected the columns you are interested in click the 'Submit Query' button again and the results should then be displayed. The results can be downloaded by selecting the required format in the drop down and clicking download results. CSV is probably the simple option that can be imported into a spreadsheet. The other options are more powerful but require you to open the files with something like TOPCAT.

There is also a much more powerful access using ADQL (Astronomy Data Query Language) but that is one of the advanced lessons. You can see what your simple query looks like in ADQL by pressing the 'Show Query' button on the basic tab.

Any problems with this reply to this message and I will try to help .

John
Data Miner & Amateur Astronomer
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